A proposed power output apparatus has an engine, a planetary gear unit that includes a carrier linked with a crankshaft of the engine and a ring gear linked with a drive shaft mechanically connected to an axle, a first motor that inputs and outputs power from and to a sun gear of the planetary gear unit, a second motor that inputs and outputs power from and to the drive shaft, and a battery that supplies and receives electric power to and from the first motor and the second motor (see, for example, Japanese Patent Laid-Open Gazette No. 2001-317385). This prior art power output apparatus sets a power to be output from the engine and a power to be output to the drive shaft, in response to a power demand required by an operator, and controls the engine, the first motor, and the second motor based on the settings. In the event of an abrupt decrease in power demand required by the operator, the control of this prior art power output apparatus estimates the possibility of a successful response to a subsequent power demand required by the operator. When a failed response is expected, a greater power than a required level corresponding to the operator's subsequent power demand is set to the power to be output from the engine. This aims to enhance the response of power output to the drive shaft to the power demand required by the operator.